# L-15 MCS 260 Mon 15 Feb 2010 : mc4pi2
#
# Illustration of lambda forms in
# a Monte Carlo method for Pi.
#
import random
n = input('Give number of samples : ')
r = range(0,n)
u = lambda i: random.uniform(0,1)
x = map(u,r)
y = map(u,r)
z = map(None,x,y)
t = lambda (x,y): x**2 + y**2 <= 1
f = filter(t,z)
p = 4.0*len(f)/n
print 'estimate for Pi : %f' % p